Boston Lynnfield 300L

This article written by Malcolm Steward was first published in Audiophile magazine (UK) in 1993.

Boston Lynnfield_300L

Boston Lynnfield 300L

For several years I have earnestly contemplated pursuing a full-time career hating Jennifer Warnes records.  Having now heard the sounds that issue from her nasal cavities courtesy of  Boston Acoustics’ Lynnfield 300L, I’ve changed my mind. A significant talent she is not, but there’s more to her voice than I’d previously realised. The 300L is the kind of speaker that can change your opinion of music. Damn it!

I first encountered this, the smaller of the two Lynnfield models, (its big brother, the 500L, is floor-standing design), then called the LP620 and in prototype form, when I visited Boston’s US headquarters a couple of years ago. The new speaker’s task, Boston told me, was to give its makers a serious presence in the high-end market. Conceived by a team that included expatriate Brit, Phil Jones, the designer responsible for the ground-breaking Acoustic Energy AE1, the speaker’s seductive appearance suggested that Boston meant business. A short demonstration reinforced that impression. A few bars of Scritti Politti’s The Word Girl was all it took: the 300L was small in stature but, oh boy, could it pack a punch and shift some air! This was the archetype small speaker with a big – for which read gargantuan – sound.

Naturally, I was eager to hear these intriguing speakers at home but was told I’d have to wait. They were not going into production until Boston’s team had them tuned to its full satisfaction. After what seemed to be an interminable wait, I received production samples from UK importers, Portfolio Marketing, in early May this year. The package, which was unduly bulky and heavy for a pair of bookshelf speakers, arrived with a second box that contained the optional, dedicated LST stands. Some days later, after a sarcastic telephone call to Portfolio, the bolts required to assemble the stands and fix the speakers to them were also couriered across the Atlantic! After nearly two years I was finally face to face with a fully rigged pair of  finished 300Ls.

The slight hiccup with the nuts and bolts aside, it was difficult not be extraordinarily impressed when this pair of  speakers arrived. Boston Acoustics certainly knows how to create the right initial impression with its customers. Having spent what in high-end terms isn’t a particularly large amount of money on the speakers, the superb, full colour instruction manuals – yes, you even get a superb, full colour booklet with the stands – suggest that the manufacturer wants buyers to be more than extremely satisfied with their purchase. It’s no exaggeration to say that these stylish brown paper covered booklets feature the sort of design and photography that normally grace coffee table art publications.

The setting up procedure proved to be easy but critical, particularly filling the LST stands with, in this instance, silver sand – lead shot is a proposed alternative but I can think of more enjoyable ways of being poisoned. Boston’s literature maintains that the filling merely increases the speakers’ stability and that there are no significant audible benefits to be realised. Wrong, wrong and thrice wrong! Filling the stands added a natural body and warmth to the sound that was missing when they were left undamped. The more heavily processed parts of The The’s Dusk album, for example, had an unpleasant hardness that made listening frustrating: large dollops of sand in each stand toned down the over exuberant high frequencies and bolstered the low end slam sufficiently to make the album seem more naturally – if still enthusiastically – balanced.

The only quibble I had with installing the speakers was getting the energetic little blighters to stand still. The stands’ floor-spikes came without locknuts and an hour or so of lively music introduced a slight wobble to the speaker/stand assembly. It was an easily cured problem but one that ought not to attend such an unashamedly high-end design.

The installation proved otherwise entirely free from strife. One thing these miniatures don’t lack is low end weight so you aren’t compelled to find wall space to reinforce their bass. That bass, however, is commendably fast and tight so if floor space is at a premium they’ll work closer to a boundary without wallowing. I parked them so that they flanked the square bay window at the end of my listening room, about half a metre clear of the rear wall and a metre away from the side walls. The speakers are ‘handed’; the left having its units on the right hand side of the baffle and vice versa.

I listened to them on the end of my regular home system, converted temporarily from active to passive operation. Primary sources were my Pink Triangle-modified Linn LP12, Naim ARO, Audio Note IoIIv turntable and Naim CDS CD player. Preamplifier was my Naim NAC52 feeding a full-range signal to two Naim NAP250 stereo power amplifiers. This bi-amplified arrangement left one 250 handling left bass and right treble signals while the second dealt with right bass and left treble, so spreading the loads on each amplifier’s power supplies. Cabling was Audio Note ANSP, an admittedly costly wire but one that has proved to be essentially neutral and not in the habit of sending the unprotected – and therefore cable-sensitive – NAP250s to the funny farm. All sources and electronics were supported by Mana Acoustics’ Reference Series stands.

The speakers benefited from a prolonged run-in period, leaving them pumping out speed metal at moderate volumes through the night and whenever I was away from them for any time. Even after their fortnight-long sojourn with me I’ll swear they were still sounding a tad sweeter and freer each time they were fired up in anger. Nonetheless, even if they were still running-in when they departed I wasn’t disappointed with our long-overdue reacquaintance. If my memory is trustworthy, I’d say that the production speakers were appreciably better than the prototypes that first interested me in the design.

What makes the sound of  these American miniatures so appealing to me is their Britishness. With the xenophobia of which I’ll doubtless be accused shelved for the moment, I’ll say that many American speakers I meet are a trifle too ‘obvious’ for my tastes. The conspicuous bass and treble perimeters they exhibit might impress some listeners but they do absolutely nothing for me. The 300Ls have strikingly clear, powerful musical extremes but they’re integrated so well with the midrange that they couldn’t be deemed flagrant by the most critical observer. At the low end, for instance, they deliver a truly inspiring authority for a compact design but it doesn’t make its presence felt at the expense of the upper octaves. Those ranges also conduct themselves with the sort of assertiveness that would be appropriate for Lennox Lewis.

Way Down Deep, a track by the not so severely adenoidal as I imagined Jennifer Warnes, included on Boston Acoustics’ latest demonstration disc, expressed the balance of the 300L’s character well; in pugilistic terms this was a speaker that floated like a butterfly and stung like a bee. Considering its tonal balance first, the 300L had a completeness, a full-bodied roundness that’s rare in compact speakers. In no way could you describe this speaker as deficient in the bass, mid-forward or bright, typical criticisms that befall ‘mini-monitors’. Jorge Calderón’s bass guitar did indeed plummet way down deep, exciting anything in the room that wasn’t anchored structurally, while at the other end of the spectrum Paulhinho da Costa and Lenny Castro’s assortment of  percussion instruments provided all the sparkle and high frequency flavouring you could rightfully demand. Warnes’ voice, and that of Blondie Chaplin in the background, showed that the 300L’s midrange was both entertaining and revealing, vividly informative but free from hyped presence. Both voices and instrumentation demonstrated the speaker’s ability to present extraordinary detail within the context of a rewarding, holistic view of the music. Its flow and overall structure were not sacrificed at the expense of any superficially appealing microscopic insight. I say that in spite of the discoveries I made about the contributions made to the tenor of her voice by Ms Warnes’ olfactory organ.

My primary concerns with a speaker or any other piece of hi-fi, however, are not of a timbral or tonal nature. In the same way that you can compensate for a spongy brake pedal on a car, I find that I can usually adapt to minor ‘inaccuracies’ in spectral balance. What I cannot endure or make allowances for is hi-fi that drives in the wrong gear for the circumstances; if Varèse’ Amériques sounds pedestrian or John Lee Hooker sounds like a white teenager when he’s playing One Bourbon, One Scotch, One Beer then I’m off to the pub. The sound of instruments can vary but the groove has to be one hundred per cent right.

The little Bostons showed the sort of temporal exactitude that keeps me home at nights. They portrayed timing and rhythmic information with a precision that was discomforting at times. Their mix of clarity and speed quickly revealed when a bass player or drummer slipped off the beat thinking that nobody was going to notice because he was getting on with business unobtrusively at the back of the mix. The 300L’s lack of smear and muddle ensured that such events didn’t pass unnoticed. The positive side of this characteristic was that the speakers allowed subtle timing devices used by musicians and the idiosyncrasies that characterise their playing styles to emerge graphically. Not only did the 300Ls portray the music’s overall temporal personality, they revealed the nuances and inflexions that gave it its individuality.

It was qualities such as this that made the Lynnfields speakers that painted pictures able to satisfy listeners who wanted an appraisal of music that was starkly realistic and those who preferred an impressionist view. Listening to John Lee Hooker’s unaccompanied (Complete Chess Folk Blues Session) recording of The Waterfront, demonstrated this dual perspective. One view was academic, giving a graphic blueprint of every note he played and every breath he took; the other was more emotional, saying more about his personal and musical character. You could choose to analyse his playing note by note or sit back and let the feeling of being in the presence of a virtuoso musician take control of your imagination.

Having read this far  without encountering any serious adverse comments about the Lynnfields I wouldn’t blame you if the words ‘rubber stamp’ were going through your mind. In mitigation I’ll say that I spent hours going through my records and CDs to find just one disc that would make the speakers fall over, or at least sound less than excellent. I failed. They coped admirably with all the torture tracks I threw at them. Whether they were asked to play Varèse or the Violent Femmes, whether the music called for delicacy, dynamics or dam-busting drama, they took it in their stride and responded accordingly. I reckon that they’re simply the most accomplished miniature speakers I’ve used. Anyone currently cataloguing high-end manufacturers should definitely make room to include Boston Acoustics’ name in  the index.

 DATA

 

PRICE                                                         £1499 (speakers) £500 (stands)

SIZE                                                            279 x 229 x 343 (HxWxD mm)

DRIVE UNITS                                           2

SENSITIVITY                                            83dB

IMPEDANCE                                             8 ohms (6.5 ohms minimum)

POWER HANDLING                                250 Watts

 

 DESIGN

  •     Speakers bolt to stands so Lynnfields are best regarded as a stand/speaker system.
  •     Two-way design using aluminium coned/domed units, with crossover point at 2.6kHz.
  •     Can be single-wired but bi-wiring or bi-amplification recommended for best results.
  •     Available in Rosewood or Black Ash veneers, the speakers have removable grilles using a polyester Lacoste stitch!

 PERFORMANCE

  •     Extraordinarily powerful and articulate bass for such a compact system.
  •     Exceptional power handling abilities ensure compression-free high listening levels.
  •     Dynamic scaling and transient response are first class.
  •     Low sensitivity and revealing nature demand use with only the finest ancillaries.

 

The Amplitude Modulation Devices

Central to the design of the Lynnfield 300 are its Amplitude Modulation Devices, the handle-like assemblies that span the drive units’ chassis, stretching across the midrange unit’s cone and the tweeter’s dome. They provide an elegant, if not exactly elegant looking, solution to the problem of controlling the resonances that invariably afflict metal diaphragms.

Phil Jones happened across the idea of using these innovative structures quite by accident. Sitting in a restaurant waiting for a take-away pizza one lunch time, he ordered a Coke. This was supplied, in typical fast-food establishment fashion, in a paper cup with a drinking straw poking through its lid. Idly blowing across the straw – as impatient speaker designers are prone to do – he realised that different notes were being produced as the level of Coke in the cup diminished. The change in level was effectively ‘tuning’ the resonant column of air inside the straw. A couple of minutes’ lateral thinking made him realise that this could be put to good use in the speakers he was developing. Why not cancel drive unit resonances by generating the same frequency but in opposing phase, something that could be arranged by placing a ‘straw’ tuned to that frequency at a particular distance in front of the driver’s diaphragm?

Jones’ work with aluminium domed and coned drivers and previous speakers using metal diaphragms had shown that while “such drivers’ stiffness and exceptional pistonic action could provide unparalleled clarity” the diaphragms tended to produce stray frequencies outside their normal bandwidth. Previous attempts at subduing this behaviour involved the use of electrical notch filters, which, to paraphrase Boston Acoustics’ literature, also obliterates an otherwise usable part of the frequency range of the driver. The AMDs therefore offer a secondary advantage; doing away with the need for electrical notch filtering means that the speaker’s crossover network can be simplified.

Although paper straws were used for the initial investigative work into the use of these devices the production items are rather more sophisticated. The AMDs are manufactured to watchmaker’s tolerances, the device on the tweeter being accurate to 0.025mm. Boston employed experts in the fields of acoustic treatment, metallurgy, tooling and cabinetry to ensure the successful application of the technology.   In the eighteen months since I first saw prototypes of this and the larger 500L speakers numerous detail changes to the design have taken place. Inevitably, getting the AMDs working to maximum effect has influenced other aspects of the drivers’ behaviour, which has been reflected in other parts of their design and that of the cabinets.

 

The speaker system

Even without its Amplitude Modulation Devices the Lynnfield 300L is an unusual speaker to behold. Both its drivers – a 130mm anodised aluminium cone woofer and a 25mm neodymium tweeter – are mounted on a single chassis and attached to the cabinet without the usual visible fixings. You’ll not find out how this is mounted to the cabinet baffle without dismantling the enclosure. Remove the tight-fitting panel onto which the hard-wired crossover components are mounted and all is revealed.

The driver array is held into the cabinet by a single bolt attached to the driver chassis at a point coincident with centre of the bass/midrange unit’s diaphragm. This anchors the chassis to a substantial internal cabinet panel that runs parallel to the front baffle. This fixing method was utilised to enhance the rigidity of the whole cabinet structure, which, it has to be said is well above-average in the robustness stakes in the first instance. It uses 1.75-inch thick walls that are composites of MDF, rubber, foam and other damping materials chosen empirically to provide a sonically inert enclosure.

The cabinet uses reflex-loading to increase output at low frequencies and the mouth of the baffle-mounted port, which exits close to the bass/mid driver, has a similar ‘gas-flowed’ profile to that seen on the original Jones-designed Acoustic Energy AE1. The pipe behind it opens into the bare, lower section of the cabinet area; the upper portion is filled with acoustic wadding.

The driver assembly remains perhaps the most interesting part of the design. Placing the two drivers close together helps to approach the notionally ideal arrangement of a point source for precise stereo imagery. That aspect shows Jones wearing his hi-fi designer hat. His design experience, of course, also includes extensive work in the professional field and this shows through in other parts of the design.  The massive, finned chassis for the driver assembly, for example, is designed to act as a heat sink for the drivers’ motor units to avoid thermally induced distortions. The bass/midrange driver topology is arranged to give linear operation right to the extreme limits of the cone’s excursion without modulation artefacts intruding. The driver surround and spider have been designed to cope with large excursions ‘indefinitely’ without the driver becoming mistuned or suffering a loss of power handling capability. The tiny driver certainly has exceptional travel, something you appreciate when you watch it  hammering away relentlessly on a low bass note!


Leave a Reply

Back to Top ↑